Method and apparatus for projecting aerial signs



Nov. 14, 1933. ca. c. EDWARDS 1,935,034

METHOD AND APPARATUS FOR PROJECTING AERIAL SIGNS Filed June 2, 1928 2 Sheets-Sheet l INVENTOR fiordwz [T Zdwardw M ATTORNEY Nov. 14, 1933. c, EDWARDS METHOD AND APPARATUS FOR PROJECTING AERIAL SIGNS Filed June 2, 1928 2 Sheets-Sheet 2 Patented Nov. 14, 1933 PATENT OFFICE AND APPARATUS FOR PROJECT- ING AERIAL SIGNS Gordon 0. Edwards, New York, N. Y.

Application June 2, 1928. Serial No. 282,309

Claims. (01. 88-24) .The present invention relates to projecting .and more particularly to a method and apparatus for projecting images into the atmosphere, or What is more commonly known as sky- 5 writing. 1

I-Ieretofore it has been necessary to provide a suitable background for the images or advertise- ,ments projected or attempted to beprojected. In some cases complicated mechanical screens 10 have been provided;. in other cases attempts have been made to utilize beams of light upon which to project the images; and in some instances dense clouds have been utilized as a background.

Any mechanical arrangement is extremely complicated and unwieldy because it has to be so large and so high in the air in order to give a sign sufiiciently large to be noticeable and in a position where it will be observedby the maximum number of persons. The construction of such a mechanicalscreen is as expensive as utilizingan electric sign; hence there is little advantage in it. The utilization of beams oi light is not practical because they do notoperate 2 as a suitable screenp---The results obtained are very, unsatisfactory. Dense cloud banks are seldom obtainable and their shape is so irregular .thattheir use as a background is difficult. They move around giving the sign a distorted appearance. It is usuallynecessary' to project at a substantial distance, when clouds are usedas a background, and the distoration prevents a clear readable sign. The apparatus, can be operated only for limited periods at times when there is little likelihood of, a large audience.

' The present invention overcomes these difficulties by providing aprojecting apparatus adapted to utilize the imperceptible particles in the atmosphere as a background to form a clear sign 40in practically all conditions of weather. The operation is not dependent ifpon cloud banks, upon beams of lightor upon mechanical screens. The image is projected in the atmosphere at night preferably about two hundred yards into the air. After proper focusing, the sign appears clearly without distoration when there is not a cloud visible in the sky. r V 0 An object of the invention is an improved method and apparatus for projecting advertising matter into the atmosphere.

, Anotherobject of the invention is to provide a method and apparatus for advertising by means of characters shownat night and to minimize the effect of atmospheric conditions on the op- 5 eration of such an apparatus. x

image upon the imperceptible moisture and other particles of the air as a background or screen hereby minimizing or eliminating the effect of atmospheric conditions on the apparatus. A

Another object of the invention is the provision of a plurality of lenses, the lens nearest the light being heat resisting and the projection lens being of glass very accurately ground.

A further object of the invention is to provide a projecting machine, the parts of which are conveniently adjustable, by an operator standing in one position, for focusing the image and for moving the image around in the atmosphere.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described and various advantages not referred to herein will occur to one skilled in the art upon employment 7 of the invention in practice. A

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, wherein 0 Fig. 1 is a diagrammatic view of the projecting apparatus with parts shown in section for the sake of clearness;

Fig. 2 is an end elevational viewvshowing the mechanism for moving the apparatus in a vertical plane about its base;

Fig. 3 is a fragmentary sectional view illustrating the adjusting mechanism;

Fig. 4 is a diagrammatic side elevational View with parts in section of another form of projector; N

Fig. 5 illustrates the adjusting features of the mechanism shown in Fig. 4;

Fig. 6 is a diagrammatic View partly in section of another formof the machine showing the lens arrangement; and

' Fig. '7 illustrates the adjusting features of the mechanism. shown in Fig. 6-. y A

Referring to the drawings, which illustrate the preferred embodiment of the apparatus, and which illustrate .also one way of practicing the method, there is shown a housing 1 with a 'refleeting. mirror 2 and an are light 4 therein. The mirror serves to reflectand project a converging beam of light through a window 5 of the housing and through a concave lens 6. The lens 6 is preferably made of quartz or some similar material which is adapted to withstand severe heat, since the rays of lightfrom the carbon arc 4 are all converged through this lens, causing it to become very hot even when properly cooled by air currents or by liquid. The shape of the lens and its position are such that the rays passing through it are transformed into a parallel beam which passes through a stencil 7 and a projection lens 8.

The stencil may be an ordinary piece of metal with the image or series of characters cut out of it to permit the rays of light to pass through. The small amount of light admitted through the stencil passes through the projection lens 8 and is projected upon the mirror 9 and reflected into the atmosphere. By adjusting the position of the stencil and projection lens as described hereinafter, a sharp image is obtained utilizing the invisible particles of the air as .a background or screen.

The curvature of the projection lens 8 which is preferably plane-convex is such that the image is properly focused about two hundred yards away. The fact that only a small portion of the light is transmitted through the projection lens 8 minimizes the amount of heating and permits a glass lens to be used which can be very accurately ground, much more accurately than quartz or some heat resisting material. I By utilizing a projection lens considerably more accurate than the ordinary commercial lens, it is possible to make the image clearly visible without a background other than the invisible particles of the air and the invisible moisture therein. This eliminates the necessity for a background such as a cloud, beam of light, or mechanical screen.

While the various elements of the apparatus may be mounted in different ways, in the preferred embodiment there is provided a pair of guide bars 10 joined together at their outer ends by a cross bar 11 to which is attached a folding leg 12 for supporting the free end of the structure. The other ends of the guide bars extend through the bracket 14 attached to the bottom of the housing 1 by means of suitable bolts.

' Intermediate the guide bars, and attached also 7 to the cross bar 11 and bracket 14, there is a pair of threaded shafts 15 and 16. These shafts have'bevelled gears 17 and 18, respectively, at the end adjoining the projector housing. The short stub shafts l9 and 20 on brackets 13 and 23,

with bevelled gears 21 and 22 meshing with the 16. The projection lens 8 also has an extension in threaded engagement with the shaft 15. By rotating the wheels 24 and 25 adjacent the projector housing it is possible to adjust the position of the stencil and projection lens very readily without requiring the operator to change his position. The positions of the lens 6 and the mirror 9 may be changed by the set screws 32.

l The mirror 9, in addition, is mounted upon a universal joint 37 so that it may be moved about to position the projected image in any desired place. The adjustability of the mirror permits a maximum adjustment of the image without movement of the projector. The disadvantage of the mirror is that it does not reflect all of the light and therefore the brilliance of the projected image is cut down by a very small percentage.

The apparatus is constructed so that the mirror may be eliminated and the beam of light projected directly into the atmosphere. The mechanism for this is shown more clearly at the left end of Fig. 1 and in Fig. 2. The supporting base or bracket 38 is connected to the floor of the housing 1 by means of the shaft 39. Gears 40 and 41 on shafts 39 and 42, respectively, permit the elevation of the entire apparatus by rotation of the crank 44 on shaft 42. A suitable counterweight 45 may be placed at the end of the projector housing to balance substantially the rods 10 and their associated parts. In this manner the entire adjustment of'the apparatus may be performed by the operator standing adjacent the projector housing by rotation of the wheels 24, 25 and crank 45.

In Fig. 4 a difierent form of apparatus is shown wherein the lens 6 is omitted. The rays of light are projected directly against a stencil 7 and the portion transmitted is properly focused by means of the projection lens 8. In this case, the projection lens issubjected to a somewhat higher temperature although only a small portion of the light emitted from the arc reaches the lens due to the fact that the major part is shielded by the opaque part of the stencil. The stencil and projection lens are adjustable in the same manner as described with respect to the apparatus in Figs. 1 and 3.

In Fig. 6 the apparatus is shown with an additional projecting lens 48. The purpose of this lens is to reduce substantially the heat transmitted to the projection lens and in condition to focus properly the beam of light so that it will be accurately projected by the projection lens. In this embodiment the stencil 7 and projection lens 8 are also adjustable as described with respect to the structure shown in Figs. 1 to 3.

In the operation of the device, the carbon sticks '4 are adjusted to give the proper degree of intensity and the lens 6 is adjusted with respect to the curvature of the mirror 2 so that the beam of light leaving the lens is substantially parallel. The lens is then fixed in position by means of the clamp screws 32. Thereafter the stencil '7 and projection lens 8 are moved to their proper. position by means of the wheels 24 and 25 to obtain a sharpimage. The mirror 9 may be moved about its universal joint so that the image may be properly located without moving the apparatus; or if desired, the mirror can be dispensed with and the entire apparatus-rotated by means of the crank 44. Any of the elements may be clamped in position by means of the set screws 32.

In the apparatus shown inFig. 4, the stencil 7 and the projection lens 8 may be positioned as noted above. In Fig. 6 the lenses 6 and 46 are clamped in proper position and the other elements are adjusted by means of the wheels 24 and 25.

It will be seen that the present invention eliminates complicated-screens used heretofore and projects the advertising-matter directly upon the normally invisible particles in the air. In fact, it is possible to view the stars through the por tion of the atmosphere where the sign is clearly projected. The effect of atmospheric conditions on the operation of the apparatus is reduced to a minmum. This is made possible by shielding the projection lens from heat and by utilizing a highly corrective glass projection lens. The apparatus is readily adjustable without necessitating a change in the position of the operator. The

efficiency is high due to the small number ofv 1 lenses and compact'arrangement.

As various changes may be made in the above embodiment without departing from the spirit of the invention, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense, as the scope of the invention is defined in the claims.

Having thus described my invention, I claim:

1. In a, machine of the class described, the

combination of a source of light, a stencil and a projection lens, a pair of co-extending threaded means, and means adjacent to each other and.

at one side of said source of light for independently operating said threaded means and adjusting the positions of said stencil and said projection lens, said apparatus being movable to direct the beam of light directly into the atmosphere and permitting the operator to adjust the elements of the apparatus without changing his position.

2. In a, machine of the class described, the combination of a source of light, a pair of guide members, a pair of threaded shafts extending between said guide members and substantially in the same horizontal plane, a stencil and a highly corrective projection lens mounted on said guide members, means for operatively connecting said stencil and lens to said shafts and guide members, means attached to said shafts and operated adjacent said source of light for rotating the shafts to adjust the positions of said stencil and said projection lens, said apparatus being movable to direct the beam of light directly into the atmosphere and permitting the operator to adjust the elements of the apparatus including the position of the projection lens without changing his position.

3. In a machine of the class described, the combination of a source of light, a guideway, a'lens mounted on said guideway adapted to receive the light and convert lit to a parallel beam, a stencil in said beam also mounted on said guideway, a projection lens adapted to receive the light transmitted through said stencil, said projection lens being slidable on said guideway,

lens mounted on said guideway adapted to re- 7 ceive the light and convert it to a parallel beam, a stencil in said beam also mounted on said guideway, a highly corrective projection lens adapted to receive the light transmitted through said stencil, said projection lens being slidable on said guideway, a reflector mounted on said guideway for projecting the light upwardly, means associated with said projecting lens and stencil adapted to engage a threaded spindle, a pair of threaded spindles extending from said source of light and along said guideway, one of said spindles being attached to the projection lens, the other spindle being attached to the stencil whereby said elements may be moved relatively with respect to each other from a point adjacent the source of light.

5. In a sky projecting apparatus, the combination of a source of light, a guideway, a lens mounted on said guideway adapted to be secured thereto, a second lens slidably mounted on said guideway and adapted to be moved with respect to said first lens, a stencil intermediate said lenses and slidably mounted on said guideway, and a pair of threaded members extending along the entire length of the guideway, one of said members being operatively connected to said second lens and the other being connected to said stencil, whereby said stencil and second lens may be moved relatively with respect to each other and said first lens.

GORDON C. EDWARDS. 

